Shape-Controllable Pulse Electrodeposition of Ultrafine Platinum Nanodendrites for Methanol Catalytic Combustion and the Investigation of their Local Electric Field Intensification by Electrostatic Force Microscope and Finite Element Method

Shape-controllable ultrafine platinum (Pt) nanodendrites have been synthesized by a facile, one-step pulse electrodeposition method in the absence of any organic additive. The particle morphology went through a transition from hemisphere, nanoflower to nanodendrite by altering anodic potential. The ultrafine tertiary branches on the dendrite exhibited an extremely small diameter of 10-20 nm. It was found that the preferential growth direction of the tips differs from the dendrite hierarchy, which is < 111 >, < 110 > and < 311 > of the trunk, secondary and tertiary branch, respectively. Catalytic performance of the platinum towards methanol catalytic combustion turned out to be in the order of dendritic > flower-like > hemispherical Pt particles. Typically, the turnover frequency (TOF) of Pt dendrites reached 0.33 mmol. min(-1). mg(-1) at 150 degrees C, which is four times that of the spherical one. Moreover, the sharp morphology-induced local electric field intensification, both under external electrostatic field and light irradiation, was demonstrated and visualized by the Electrostatic Force Microscope (EFM) and finite element method. (C) 2014 Elsevier Ltd. All rights reserved.